This tab covers both the parameters and the results used in the analysis of both single anchors and anchor groups. All input parameters and results should fit on two printed pages. Note that both the 2D sketch contained within the input (and therefore printed in the output), and the 3D model are updated in real time as you change the design parameters.
Design Specification
Select either ACI 318-14, ACI 318-11 (both referred to as ACI in the following text) or the 8th Edition of the PCI Handbook (PCI). All of the ACI references herein are from ACI 318-14.
Project Information
Project: Project name.
Location: Location of the project.
Date: Date printed on the report (defaults to the current date).
Client: Name of the client.
Designer: Name of the design engineer.
Job Number: Job number for the project.
Description: Long form description for the project.
Anchor Information
The dimensions of the anchor input in this section are show in the dynamic, scaled 2D sketches below the input. Some of the anchor dimensions can be input in the both the sketch and the accompanying text box for that dimension.
Ductility: Anchors can be either ductile or brittle. This designation is only used in the ACI calculations (17.3.3) to select the default resistance factors for steel. PCI assumes that steel anchors are always ductile.
Yield: Yield strength of the anchor.
Ultimate: Ultimate tensile strength of the anchor
Type
Headed Studs: Headed anchor studs welded to a flat plate, typically in groups of four or more. Furthermore, the plate is assumed to be embedded in concrete, with the face of the plate flush with the face of the concrete. Consult the manufacturer’s catalog for the following dimensions:
Head Diam.: The diameter of the head is used in conjunction with the shank diameter to calculate the effective surface area of the head.
Eff. Length: The effective length is measured from the base of the head to the back face of the plate.
Shank Diam.: The diameter of the shank is used to calculate the area of the stud.
L Bolts/J Bolts: For the purposes of calculations, L and J bolts are not assumed to be rigidly attached to a plate, and the plate is assumed to be surface mounted to the concrete, not embedded.
Bolt Diam.: The diameter of the bolt is used to calculate the area of the bolt.
Threads per [unit of length]: # of threads per unit of length.
Eff. Length: The distance from the face of the concrete to the outermost part of the bolt.
Hook Width: For J bolts, the hook with is the out to out dimension of the hook. For L bolts, the hook width is the length of the hook.
DBA: DBA is a deformed bar anchor, typically a straight mild rebar butt welded to an embedded plate in groups of 4 or more. Similar to headed studs, with the anchorage provided by the bar deformations, instead of a head.
Bar Size: Bar size is the US designation, 3-11.
Eff. Length: The effective length is measured from the back face of the plate to the end of the bar.
Anchor Group Layout
The spacings and edge distances of the anchor group input in this section are shown in the dynamic, scaled 2D sketches below the input. Some of the anchor dimensions can be input in the both the sketch and the accompanying text box for that dimension.
Anchor Grid: The spacings and # of anchor devices are defined in this section. It is assumed that the all of the rows and columns will have the same # of anchors.
# Rows/# Columns: Number of rows and columns in the anchor grid.
Row Spacing/Col. Spacing: The program assumes that all spacings are equal.
Concrete Edge Distances (to Plate): Pressing the infinity button will mark that edge distance as infinite. Note that doing this will cause the algorithm to skip some calculations. If you do not want to skip any calculations, but still want to model a very large edge distance, set the edge distance to 99 inches.
Top edge to first row: Distance between the top edge of the plate and the centerline of the closest row.
Left edge to first col.: Distance between the left edge of the plate and the centerline of the closest column.
Concrete Properties
This section contains both dimensional and material properties for the concrete which contains the anchors.
Member Thk.: Total thickness of the concrete member in which the anchors are embedded.
State: The concrete member can have one of two states, Uncracked or Cracked. See the discussions in ACI 17.3.2 or PCI 6.5.3 for the effect of uncracked/cracked concrete.
f’c: Final compressive strength of the concrete (often referred to as the 28-day strength).
λ factor: The λ factor is a material reduction factor based on the density of the concrete. Typical values are 1.0 for normal weight concrete and 0.75 to 0.85 for lightweight concrete.
Supplementary Reinf.: In addition to the state of the concrete (cracked or uncracked), supplemental reinforcement may also be present that will effect the calculations. See the discussions in ACI 17.3.2 or PCI 6.5.3 for the effect of supplemental reinforcement.
Tail Bars
Include tail bars: If a tail bar is attached to the plate, then you can define the properties of that tail bar here. Note that you can only have one tail bar at a time. The tail bar may or may not be a single bar (although the sketches will show it as such) but rather the total area of steel required or provided. Therefore, development length is not checked.
As: Total cross sectional area of the tail bar or bars.
Yield: Yield strength of the tail bar or bars.
Direction: Since the tail bar is used to resist any applied parallel load, it should be placed opposite the direction of the load.
Angle: Tail bars are typically angled to provide cover, however this will reduce the effective area.
Loading
# Rows/# Cols Resisting Tension Force: # of rows or columns that that will be used in the analysis to calculate the tension capacity of the group. For vertical loads (in the Y direction), use the # of rows. For horizontal loads (in the X direction) use the # of columns.
Parallel: If the applied load or loads are parallel to the surface of the concrete, you can input them here. Note that you can have simultaneous parallel and perpendicular loads.
Vux/Vuy: Factored vertical applied parallel load. The Y direction is up and down in the plan view, while the X direction is left/right.
Ecc,y/Ecc,x/Ecc,z: The Y direction is up and down in the plan view, while the X direction is left/right, and the Z direction is in and out of the screen in the plan view.
Perpendicular: If the applied load is perpendicular to the surface of the concrete, you can input it here. Note that you can only have one perpendicular load.
Ecc,x/Ecc,z: The X direction is left/right in the plan view, while the Z direction is in and out of the screen in the plan view.
Plate Information
Height: Height of the plate as shown in the plan view below.
Width: Width of the plate as shown in the plan view below.
Thick: Thickness of the plate.
Bracket Dimensions
Support brackets are commonly welded to embedded plates, but are not required in this analysis.
Eff. Depth: Distance from center of the tension force to the extreme compression ‘face’ (the bottom edge of the vertical element(s) of the bracket).
Eff. Width: Width of the bracket that is compressing the concrete. May be the sum of the width of the vertical elements of the bracket.
Resistance Factors
Include additional strength reduction for seismic design: ACI 318 Section 17.2.3.4.4 contains additional reduction factors in seismic zones. Select this option to include them in the analysis.
Concrete - Tension/Shear/Pullout: Resistance factors used in the calculation of the concrete capacity.
Steel - Tension/Shear: Resistance factors used in the calculation of the steel capacity.
Design Summary
The Design Summary lets the user see all of the critical analysis results in one place. Additionally, the controlling mode is listed in the top bar, essentially giving you a single number rating of the anchor group. Note that if you do not have a bracket, you should not assign a Z eccentricity to your X or Y loads. This will cause the program to display an infinity symbol for some values in the Design Summary box (an infinity symbol in the analysis results generally signifies that the analysis engine has attempted to divide by zero).
Interaction of Tension and Shear
If the applied forces result in both shear and tension applied to the anchor group, the relevant equations/values are shown here.
Resultant Forces
If any of the applied forces create a moment to be resisted by the anchor group, this moment (and the additional tension force due to the applied moment) will be shown here.
Concrete - Breakout Strength (Shear/Tension)/Pryout Strength (Shear)/Pullout Strength (Tension)/Blowout Strength (Tension)
See the code/handbook reference in the title block for a description of these specific computations.
Steel – Shear Capacity/Tension Capacity
See the code/handbook reference in the title block for a description of these specific computations.
Additional Checks and Design Notes
These are required checks from ACI 318, and will be checked even if you select PCI Handbook as your Design Specification.